Tool handle



July 24, 1928.

L. B. ANDRESEN TOOL HANDLE FIG. 5

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Filu@ shaft by. means Aot a Patented Jaiy 24, i928.

ILLINOIS.

Application inegi November ia, i923.

y BNNDENBENG iiNnnnsiiN, CEMI riifrfinnson DENTAL. siirPLY co., on

stares NNiiiiroLis, iviiNNiiso'rA, sr.'` BAUL, MINNESOTA, Acoitromifrioivl oF Perrier orties.

AssIGNonmo F.

Toon (HANDLE.

This invention relatestonew and useful improvements in tool handlesadapted for use to hold and supportsmall tools such as dental drillsandbuirs and more particularly relates to improvements in such handlesas are commonly employed by dentists in the work of preparing teeth fordental repairs,

such as fillings, inlays, bridges,

ot cleaningk and polishing teeth.

in the work To do this worl; employed, and it inea-ns be providedditlerent easily and rapidly ,beL changed of time.

Dental tool handles of etc., and also kinds of tools are is lthereforedesirable that whereby such tools may wit-houty loss ordinaryconstruction are usually provided` with a rotatably mounted driven:member or shaft having a clutch mechanism provided at thetool endthoreoil and adapted .to clamp securely the tool therein when in use.

ment is transmitted `to the suitable means, securedv thereof, which isadapted the usual dental motor.

Rotary move driven member or grooved pulley orlother to the upper endtobe operated by When `using such a tool handle,'and especially whenusing such toolsvas a drill or burr, often siibiected to a consi thedriven shatt is derable end thrust or load, which may be in eitherdirection, de-

pending upon the action of the tool. i Suitable tliiust bearings aretherefore provided adj acent the tool end to; take up this load and ofthe handle, adapted thus permit the shaft to rotate freely` withoutdanger of binding.

`lilowever, `in riisiiigya tool handle such as the one above described,

diiiiculty is often experienced in that line particles ofemery andpumiee' stone, mixed with saliva,

work

around the rapidly revolving shanlcof the thereto..

andv clutch mechbearing thus becoming ui'inecessarily worn and damagedsanitary condition, bearing and from the handle and tl and alsotomaintain itin a' it is necessary associated parts, be removed that theioroughly,` cleaned aiter .usage in ordertha-t all gritand foreignmatter` may be removed practically necessitates therefrom. This disassembling the tool handle, which is often inconvenient for the user,and

lead toliieglect, withv theV therefore t has a tendency to subsequentruina- Serial No. 674,217;

on of the bearing in a comparatively shorttime. p t

lny the construction of. `the novel tool handle `featured in lthisinvention, means are provided Jfor positively preventing any grit or'foreign matter from entering `tlielbearing when the handle is in use,thereby protecting the bearing and associated parts from. unnecessarywear and damage and also eliminating the, neessity` of disassembling thehandle each time it has been used. This handle.r

The object of this invention, therefore is to providean improvedtoolhandle.

Otherobjects of the invention will. more fully appear 'from thefollowing description and the accompanying' drawings and will be pointedout in the annexed claims.

In the drawings, there has been, disclosed a. lstructure designed tocarry outthe various objects of the invention, but it is to beunderstood Vthat the invention is not confined to the exactffeaturesshown as various changes may be made within they scope of the claimswhich follow.

In the drawings:y v

Figure l` is a longitudinal sectionalview of my improved tool handle,showing the sha-niiet a1 toolpositionedbetween the jaws of tlie clutch,and alsoshowing the mea-ns providedfat the tool end of the handle forpreventing foreign matter from entering the bearing-W;

Figure 2 is a similar view, partially in side elevation, to show theclutch in open position;

` Figure 3 is a cross-sectional view. onthe line 3-3 of Figure l;

Figure 4f. isapartiil sectional view of the lower or tool end of ythehandle with the tip cap removed ytherefrom t Figure r5 isk afviewshowing thel cap removed tromthetool handle.; and i Cil Figure 6 is alperspective view of the packing' washer removed from the cap.

In the selected embodiment of the invention here shown, for purposes ofdisclosure, there is illustrated a dental tool handle coinprising'acylindrical casing 11 preferably having a lower reduced end portion 12upon which. is mounted the usual outer shell 13, of any suitablenon-conductive material, for the purpose of providing a` convenienthandgrip for the user.

The upper terminal end of the casing 11 is exterior-ly threaded toreceive a threaded head 14, havinp an upwardly extending integral boss15 provided thereon. This'boss is concentric with the axis of the toolhandle and functions to provide a bearing' for the usual tool handlesupporting,- arm 16, having its other end connected to the usualsupporting` means, not shown. An annular groove or recess 17 ispreferably provided in the boss 15 to receive the reduced end portion ofthe screw 18. yThe usual fibre block 19 is also shown yieldably heldagainst the periphery of the hub by meansvofl the lusual compressionspring 21 and adjusting;` screw '22 and has the usual function ofcreating a slight friction in the bearing` for the purpose of retaininga good fit between the hub 15 and the bore of the arm 1G, at the sametime permitting the tool handle to berotated relative to the supporting'arm.

One of the important features of invention resides in the means providedat the upper end of the handle for taking up the axial load or' thrustof the drive shaft, in either direction, instead of the usual thrustbearing usually provided for this purpose and mounted adjacent the loweror tool end of the handle.

As shown in Figure 1, the upper portion of the casing 11 is boredrelatively large and is internally threaded to receive an adjusting nut-23, having' the usual sockets 24 provided in the upper face thereof bymeans of which it may be relati v ily rotated within the caf-iin?,v toadjust its relative position therein. A set screw 25 is preferablyprovided to lock thenut 23 in adjusted position. This nutfunctions toprovide a. seat for a suitable antifriction thrust bearing` 26 mountedupon a hollow drive stem 27, the lower portion of which passes throughthe adjusting nut 23 and is tei'- ininally secured to the upper end of arelatively larger hollow drive shaft 28 by .such means as the threads29. An integral annular flange 31 is formed on the central portion ofthe stem 27 adapted to have its lower face bearing against the upperface of the bearing' 26. A similar thrust bearing' 32 is mounted on thestem 27 above the iangey 31 and an adjusting nut 33 is mounted on theupper portion of the stem in abutting relation to the bearing 32. The

th is formed upper adjusting nut is likewise iny threaded engagementwith the upper inner threaded portion of the casing 11, ,so that theposition of the drive stem 27 andbearings 26 and 82 may be' relativelyand properly adjusted within `the easing. The upper end of the nut 33preferably extends above the upper end of the casing so that when thehead V14 is screwed downwardly the inner face 34 thereof will bearagainst the nut and thus lock it in adjusted position.

The two adjusting nuts 223 and 33 are preferably bored to provide arunning` fit for the stein 27, rotatably mounted therein. The stem 27also preferably extends above sor the liner face of the boss 15 and has'the usual' grooved drive pulley 35 lixedly mounted thereon. The lowerface' of the pulley 35 is preferably provided with a hub 3G which iscounterbored to receive the fprojecting end of the boss 1.5 and toprovide a running` iit therefor. By thus partially mounting;` thepulleyupon the end ofthe stationary hub y15,'the radial load of the`shaft willl be taken up by the hub andv not by the stem 27, whichloosely passes through the boss 15, as shown. j y

As hercinbefore stated, the upper end of the hollow drive shaft 28 isterminally secured to the lower vend of the drive stein 27, anddownwardly extends therefrom substantially the entire length of thehandle. The lower end ofthe shaft is preferably to rprovide a reducedend portion 37 adapted toreceive a suitable bearing` sleeve 38` securedthereto. The lower or tool vend of the reduced portion 12 of the casing`l1 is terminally threaded to receive an rend piece 39 which is .suitablybored to provide a running lit for the sleeved end of the drivek shaft28. This y end piece is slightly conical in y'shape and is' locked tothe casing"preferably by means of a headed screw 41, in threadedengagement with the wall of the end-piece 39. The reduced end portion 37of theflrive shaft is, provided with an aperture 42 through which the'tool shank may be insertee nism. l

Another important feature of this invenl to the'clutoh kmerhation. isthe novel clutch mechanism provided for securing` the tool to the handlewhile in use. Such means consists preferably in the provision of a pairof opposed clutch meinbers'43 pivotally'mounted upon a pivot pin 44preferably having'fits ends secured to the drive shaft'QS,v as shown inFigures 3 and 4. These yclutch members are positioned withiny anelongated opening 45 provided inthe drive shaft 28 adjacent the lowerend thereof, and rare provided with opposed clutch jaws 46 adapted tormly `@grip the tool shanlr when inserted therein through the aperture42. The upper end of each clutch memberf43 is terminally provided withwith said shaitand adapted to clutch a tool shank, thrust bearings forsaid shaft mount-- ed adjacent the drive end of said tool handle, l

shaft adjacent the drive end of said handle,

thrustbe' 'ings engaging said flange, and members adjustably securedto'said casing and engaging said thrust bearings whereby end play may betaken up and whereby said shaft may be relatively moved in either axialdirection relative to said easing. f

6. A dental tool handle, comprising in eon'ibination, a casing, a. driveshalt therein, a clutch associated with said shaft and adaptedto Clutcha tool shank, an annular liange provided upon said shaft' adjacent thedrive end of said handle, thrust bearings engaging said iange, anadjusting members mounted upon said shaftbetween said l'lange and saidyclutch and engaging one of said bearings, said `member having'athreaded engagement with said easing, an adjusting nut also mounted uponsaid shaft at the` opposite side of said flange and engaging the otherof said bearings, a portion of said ad- 'ustinr nut extendinfr-be 7ondthe end oitsaid l :D b u gageinent with the exterior of said easingcasing, and a cap received in threaded eny 4o adapted to engage said nutto lock itin ad-` with the shalt and adapted to `clutch a. tool l shank,an annular flange on the shaft, bear` ing members on the shaft andengaged with said flange, and adjusting members mounted upon said shaftand engaged with said bearing men'ihers, said members being-receivedinfk threaded engagement with said casing and adapted for axial movementto tale'up end play said hearings and whereby the position e oftheeluteh with relation to the easing may be maintained. i

8. l'n a dental hand piece, the combination of a easing, a drive shaftrotatably borne in the casing and adapted to have a tool opera tivelyconnected thereto adjacent one end of the easing, an annular integralflange on the shaft. thrust hearings on the shaft and engaged with saidflange, adjusting nuts seeured to the casing and engaged with saidbearings to talre up end play oli the shaft in either direction, saidbearings being all located within the casing relatively remote from thetool end thereof to proteet the bearings lrom foreign matter entrant atthe tool end of the easing. l

In witness whereof, I have hereunto set my hand. w l i LAUmTz BREDENBERGANDRESEN.

inwardly extending rounded projections 47,

between which a wedge 48 is inserted to spread the two members andthereby cause the jaws 4G to clutch the tool shank and thus 'securelyclamp it to the revolving shaft 28,

. of the clutch members may providea stop Afor theend of the tool shank,as shown, when inserted therein.

The upper portion of the wedge 4S is preferably cylindrical in form andfitted to' A clutch yrod l the boreof thel drive shaft. 51 is secured tothe wedge 48 and upwardly extends therefrom through the hollow stein 27.A suitable finger grip 52 is secured to the upper end of the rod bymeans of which the wedge 48 may be partially withdrawn from between therounded projections 47 of the clutch members 43, to release the clutch.The body of the wedge is preferably of such length that the upper endthereof will terminali;7 engage the lower end of the stem 27 before thepoint of the wedge has been con1- pletely withdrawn from lbetween theclutch members,as shown in Figure 2. Thus, the

wedge will always be in position to readily end-piece 39 and is securedthereto in such manner that it may quickly and readily be removedtherefrom. A substantially T- shaped opening` 54 is provided adjacentthek uppeil edge thereof, adapted to receive the head of the screw 4lwhen the cap is positioned upon the casing tip, as shownin Figures l andE2. A slight rotation ofthe cap, after having been thus positioned willcause the head of the screw 41 to engage one end of the opening 54,thereby locking the cap Ato the casing end-piece and therefore to thehandle. A packing washer 55, (shown in Fig. (i) having an aperture 56provided therein. is removably mounted within the cap adjacent theterminal end thereof, adapted to be clamped against the bottom face ofthe casing end-piece 39 and thereby positively prevent any foreignmatter from enteringl the casing. This packing washer may readily beremoved and replaced by a new one should it become worn or unsanitaryfrom use, by simply removing the cap' 53 from the tool handle. as abovedescribed and as shown in Fig. 5.

From the foregoing description, therefore,

it will readily be seen and understood that f by the removal of theusual thrust bearing cap 53.

from thek 'tooll end of the handle and by mounting it adjacent the upperor drive endv thereof, itjwill be practically impossible for any foreignmatter to enter the bearing, thereby eliii'iinating the usual rostoflfrequentlyfhaving to renew sucha bearing. A radial guide bearing isprovided adjacent the tool end ofthe handle, and this bearing protectedagainst grit and foreign matter by means ofthe packing Washer 55 and tipThe clutch mechanism featured is also of verysimple and inexpensiveconstruction, comprising but few parts, and all c pivotally mountedwithin theI drive shaft,

a clutch-actuating ineansslidably mounted within the driveshaft andhaving one rend outwardly projecting through one end of the toolhandlefto yprovide lan operating means therefor, anda demountable endcap having a removable packingxwasher therein, fitted over the. end ofthecasing end-piece to prevent dust and gritfrom entering the' casing.

2. In a dentaltool handle, the combination of a casing having ademountable cap at the drive end thereof,` a driveshaft mounted withinthe easing,a driving means secured to one end of the drive shaft, meansadjacent the drive end of the casing for longitudinally adjusting thedrive shaft and for taking up end play thereof, a clutch mechanismmounted'within the drive shaft, ay clutch-actuating means slidablymounted within said shaft and operable from one end of the handle, adeinountable cap having` a removable packing therein, mounted adjacentthe tool end of the handle,`an ;l means at the drive end of the handlefor supporting said handle.

ln a dental t-ool handle, the combination of a casing a flangeddrive-shaft borne in the casing, tool-gripping means within the casingoperatively connected to the shaft, thrust bearings mounted on the shaftand engaged with the opposite sides of the Harige on said shaft, andmeans engaged with the casing and operable to take up end play in saidthrust bearings, while maintaining the same relative position of saidltool-gripping means to the casing.

' 4. A*dental tool handle, comprising in con'ibination, a casing, adrive shaft rotatably mounted therein, a clutch associated

